The present invention relates to a facsimile machine and a facsimile communication method, and in particular, to a facsimile machine and a facsimile communication method by which communication of fax data can be completed even when a communication sequence according to the ITU-T V.34 mode stopped.
Among various types of information communication means provided today, information communication by facsimile has a strong point in that text, characters, images or whatever on a sheet can be sent easily and directly, and fax machines have come into wide use in many countries. Generally, fax machines are designed to execute communication (transmission and reception) of image data according to ITU-T recommendation. These days, some facsimile machines on the market are provided with modems according to ITU-T V.34.
However, in the case where a communication sequence according to ITU-T V.34 is stopped for some reasons, a typical conventional fax machine provided with the ITU-T V.34 modem waits for he next signal until a predetermined time-out period passes. When the time-out period has elapsed, the conventional fax machine judges that some communication error has occurred and thereby disconnects the connection (communication with another facsimile machine). Therefore, communication of fax data can not be completed, and what is worse, the sender has to be charged with connection charge (communication charge) in vain.
In communication in the ITU-T V.34 mode, communication bit rate is determined based on judgment on the condition of the communication line. The sequence for determining the communication bit rate is executed before the first primary channel (i.e. before the first image data communication phase). However, under impaired line conditions, the sequence for determining the communication bit rate can not be completed, and sometimes the sequence have to be stopped even before completing the judgment of the condition of the communication line. In such cases, the modem maintains its status and waits for the next signal until a predetermined time-out period passes. When the time-out period has elapsed, it is judged that a communication error occurred and the communication is disconnected. After the disconnection, another call is executed by the sender (or a transmitter facsimile machine) and the communication of fax data is completed, however, the sender has to be charged with connection charge twice.
It is therefore the primary object of the present invention to provide a facsimile machine, by which communication of fax data can normally be completed with reliability even in the case where the communication sequence according to the ITU-T V.34 stopped, and thereby waste of communication charge can be prevented.
Another object of the present invention is to provide a facsimile communication method, by which communication of fax data can normally be completed with reliability even in the case where the communication sequence according to the ITU-T V.34 stopped, and thereby waste of communication charge can be prevented.
In accordance with a first aspect of the present invention, there is provided a facsimile machine which is provided with functions for executing communication of image data according to ITU-T V.34 mode, comprising a communication means, a timer means and a control means. The communication means executes a communication sequence for transmitting the image data to a communication line of a telephone network or receiving the image data from the communication line. The timer means counts a time concerning suspension of the communication sequence according the V.34 mode which is executed by the communication means. The control means changes the communication means into a state for executing communication of image data according to ITU-T V.17 mode, V.29 mode or V.27ter mode, in the case where the timer means counted to a predetermined period.
In accordance with a second aspect of the present invention, in the first aspect, the timer means counts a time during which the communication sequence according to the V.34 mode keeps stopping in a stage before the communication means executes communication of image data using the first primary channel, as the time concerning suspension of a communication sequence. The control means changes the communication means into the state for executing communication of image data according to the V.17 mode, the V.29 mode or the V.27ter mode, in the stage before the first primary channel.
In accordance with a third aspect of the present invention, in the first aspect, the timer means counts a time during which the same communication sequence according to the V.34 mode is repeated in a stage before the communication means executes communication of image data using the first primary channel, as the time concerning suspension of a communication sequence. The control means changes the communication means into the state for executing communication of image data according to the V.17 mode, the V.29 mode or the V.27ter mode, in the stage before the first primary channel.
In accordance with a fourth aspect of the present invention, in the first aspect, the control means selects the communication mode (to which the communication means should be changed) out of the V.17 mode, the V.29 mode and the V.27ter mode, based on communication of a DIS (digital identification signal) and a DCS (digital command signal) with a facsimile machine on the other side.
In accordance with a fifth aspect of the present invention, there is provided a facsimile communication method for a facsimile machine that is provided with functions for executing communication of image data according to ITU-T V.34 mode. The facsimile communication method comprises a communication step, a timer step and a communication mode change step. In the communication step, a communication sequence according to the V.34 mode is executed by a communication means for transmitting the image data or receiving the image data. In the timer step, a time concerning suspension of the communication sequence according the V.34 mode is counted by a timer means. And in the communication mode change step, the communication means is changed into a state for executing communication of image data according to ITU-T V.17 mode, V.29 mode or V.27ter mode, in the case where the timer means counted to a predetermined period.
In accordance with a sixth aspect of the present invention, in the fifth aspect, the timer means in the timer step counts a time during which the communication sequence according to the V.34 mode keeps stopping in a stage before the communication means executes communication of image data using the first primary channel, as the time concerning suspension of a communication sequence. The communication mode change step is started in the stage before the first primary channel.
In accordance with a seventh aspect of the present invention, in the fifth aspect, the timer means in the timer step counts a time during which the same communication sequence according to the V.34 mode is repeated in a stage before the communication means executes communication of image data using the first primary channel, as the time concerning suspension of a communication sequence. The communication mode change step is started in the stage before the first primary channel.
In accordance with an eighth aspect of the present invention, in the communication mode change step in the fifth aspect, the communication mode to which the communication means should be changed is selected out of the V.17 mode, the V.29 mode and the V.27ter mode, based on communication of a DIS (digital identification signal) and a DCS (digital command signal) with a facsimile machine on the other side.